Wearable UV Monitor May Cut Nonmelanoma Skin Cancer Risk

M. Alexander Otto, MMS, PA

April 05, 2022

The study covered in this summary was published on medRxiv.org as a preprint and has not yet been peer reviewed.

Key Takeaway

  • Use of an ultraviolet (UV) dosimeter that warns wearers when they've been in the sun too long was associated with a reduction in nonmelanoma skin cancers among elderly people in a small pilot study.

Why This Matters

  • It's hard for people to know when they're being exposed to too much UV radiation.

  • A wearable UV dosimeter (the Shade UV dosimeter, Shade) provides real-time information to users though a smartphone application.

  • The study shows that the device may help older people avoid overexposure to UV radiation and reduce the likelihood of skin cancer.

Study Design

  • Investigators randomly assigned 47 persons to UV protection counseling and 50 others to use of the Shade UV dosimeter between April and July 2018 and followed them for 6 months.

  • Participants were White, the mean was 66 years old, and they had histories of actinic keratoses. About two thirds were men.

  • Participants were encouraged to wear their dosimeter every day.

  • The devices, which were worn on the chest, measured the UV index every second and cumulative UV dose every 6 minutes.

  • The information was relayed to the smartphone app, which displayed the degree of UV exposure and alerted participants when they had exceeded a preselected threshold.

  • The application adjusted the degree of UV exposure to account for sunscreen use.

Key Results

  • At 6 months, for the group that wore the device, there was a 20% lower ratio of incidence rates for actinic keratoses (P = .44)

  • For the group that wore the device, there was also a 95% lower ratio of incidence rates for nonmelanoma skin cancers (P = .024).

  • Device compliance was above 75% throughout most of the summer and dropped below 50% after November.


  • The study was short and the sample size was small.

  • The population came from a single recruiting site in New York City.

  • UV exposure in the control group was unknown.


  • The study was funded by dosimeter manufacturer Shade, which also provided the dosimeters and smartphone application.

  • Two investigators are employees and shareholders of Shade, and one is an advisor and shareholder.

This is a summary of a preprint research study, "A Randomized Trial of a Wearable UV dosimeter for Skin Cancer Prevention," led by George Varghese of Weill Cornell Medicine, New York City. The study has not been peer reviewed. The full text can be found at medRxiv.org.

M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who has worked for several major news outlets before joining Medscape and also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.

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